clang/test/SemaCXX/warn-comma-operator.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -Wcomma -std=c++11 -verify %s
   2 // RUN: %clang_cc1 -fsyntax-only -Wcomma -std=c++11 -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
   3
   4 // RUN: %clang_cc1 -fsyntax-only -Wcomma -x c -std=c89 -verify %s
   5 // RUN: %clang_cc1 -fsyntax-only -Wcomma -x c -std=c99 -verify %s
   6 // RUN: %clang_cc1 -fsyntax-only -Wcomma -x c -std=c11 -verify %s
   7 // RUN: %clang_cc1 -fsyntax-only -Wcomma -x c -std=c17 -verify %s
   8
   9 // int returning function
  10 int return_four() { return 5; }
  11
  12 // Test builtin operators
  13 void test_builtin() {
  14   int x = 0, y = 0;
  15   for (; y < 10; x++, y++) {}
  16   for (; y < 10; ++x, y++) {}
  17   for (; y < 10; x++, ++y) {}
  18   for (; y < 10; ++x, ++y) {}
  19   for (; y < 10; x--, ++y) {}
  20   for (; y < 10; --x, ++y) {}
  21   for (; y < 10; x = 5, ++y) {}
  22   for (; y < 10; x *= 5, ++y) {}
  23   for (; y < 10; x /= 5, ++y) {}
  24   for (; y < 10; x %= 5, ++y) {}
  25   for (; y < 10; x += 5, ++y) {}
  26   for (; y < 10; x -= 5, ++y) {}
  27   for (; y < 10; x <<= 5, ++y) {}
  28   for (; y < 10; x >>= 5, ++y) {}
  29   for (; y < 10; x &= 5, ++y) {}
  30   for (; y < 10; x |= 5, ++y) {}
  31   for (; y < 10; x ^= 5, ++y) {}
  32 }
  33
  34 // Test nested comma operators
  35 void test_nested() {
  36   int x1, x2, x3;
  37   int y1, *y2 = 0, y3 = 5;
  38
  39 #if __STDC_VERSION >= 199901L
  40   for (int z1 = 5, z2 = 4, z3 = 3; x1 <4; ++x1) {}
  41 #endif
  42 }
  43
  44 // Confusing "," for "=="
  45 void test_compare() {
  46   if (return_four(), 5) {}
  47   // expected-warning@-1{{comma operator}}
  48   // expected-note@-2{{cast expression to void}}
  49   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:7-[[@LINE-3]]:7}:"static_cast<void>("
  50   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:20-[[@LINE-4]]:20}:")"
  51
  52   if (return_four() == 5) {}
  53 }
  54
  55 // Confusing "," for "+"
  56 int test_plus() {
  57   return return_four(), return_four();
  58   // expected-warning@-1{{comma operator}}
  59   // expected-note@-2{{cast expression to void}}
  60   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:10-[[@LINE-3]]:10}:"static_cast<void>("
  61   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:23-[[@LINE-4]]:23}:")"
  62
  63   return return_four() + return_four();
  64 }
  65
  66 // Be sure to look through parentheses
  67 void test_parentheses() {
  68   int x, y;
  69   for (x = 0; return_four(), x;) {}
  70   // expected-warning@-1{{comma operator}}
  71   // expected-note@-2{{cast expression to void}}
  72   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:15-[[@LINE-3]]:15}:"static_cast<void>("
  73   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:28-[[@LINE-4]]:28}:")"
  74
  75   for (x = 0; (return_four()), (x) ;) {}
  76   // expected-warning@-1{{comma operator}}
  77   // expected-note@-2{{cast expression to void}}
  78   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:15-[[@LINE-3]]:15}:"static_cast<void>("
  79   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:30-[[@LINE-4]]:30}:")"
  80 }
  81
  82 void test_increment() {
  83   int x, y;
  84   ++x, ++y;
  85   // expected-warning@-1{{comma operator}}
  86   // expected-note@-2{{cast expression to void}}
  87   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:3-[[@LINE-3]]:3}:"static_cast<void>("
  88   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:6-[[@LINE-4]]:6}:")"
  89 }
  90
  91 // Check for comma operator in conditions.
  92 void test_conditions(int x) {
  93   x = (return_four(), x);
  94   // expected-warning@-1{{comma operator}}
  95   // expected-note@-2{{cast expression to void}}
  96   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:8-[[@LINE-3]]:8}:"static_cast<void>("
  97   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:21-[[@LINE-4]]:21}:")"
  98
  99   int y = (return_four(), x);
 100   // expected-warning@-1{{comma operator}}
 101   // expected-note@-2{{cast expression to void}}
 102   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:12-[[@LINE-3]]:12}:"static_cast<void>("
 103   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:25-[[@LINE-4]]:25}:")"
 104
 105   for (; return_four(), x;) {}
 106   // expected-warning@-1{{comma operator}}
 107   // expected-note@-2{{cast expression to void}}
 108   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:10-[[@LINE-3]]:10}:"static_cast<void>("
 109   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:23-[[@LINE-4]]:23}:")"
 110
 111   while (return_four(), x) {}
 112   // expected-warning@-1{{comma operator}}
 113   // expected-note@-2{{cast expression to void}}
 114   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:10-[[@LINE-3]]:10}:"static_cast<void>("
 115   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:23-[[@LINE-4]]:23}:")"
 116
 117   if (return_four(), x) {}
 118   // expected-warning@-1{{comma operator}}
 119   // expected-note@-2{{cast expression to void}}
 120   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:7-[[@LINE-3]]:7}:"static_cast<void>("
 121   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:20-[[@LINE-4]]:20}:")"
 122
 123   do { } while (return_four(), x);
 124   // expected-warning@-1{{comma operator}}
 125   // expected-note@-2{{cast expression to void}}
 126   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:17-[[@LINE-3]]:17}:"static_cast<void>("
 127   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:30-[[@LINE-4]]:30}:")"
 128 }
 129
 130 // Nested comma operator with fix-its.
 131 void test_nested_fixits() {
 132   return_four(), return_four(), return_four(), return_four();
 133   // expected-warning@-1 3{{comma operator}}
 134   // expected-note@-2 3{{cast expression to void}}
 135   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:3-[[@LINE-3]]:3}:"static_cast<void>("
 136   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:16-[[@LINE-4]]:16}:")"
 137   // CHECK: fix-it:{{.*}}:{[[@LINE-5]]:18-[[@LINE-5]]:18}:"static_cast<void>("
 138   // CHECK: fix-it:{{.*}}:{[[@LINE-6]]:31-[[@LINE-6]]:31}:")"
 139   // CHECK: fix-it:{{.*}}:{[[@LINE-7]]:33-[[@LINE-7]]:33}:"static_cast<void>("
 140   // CHECK: fix-it:{{.*}}:{[[@LINE-8]]:46-[[@LINE-8]]:46}:")"
 141 }
 142
 143 #ifdef __cplusplus
 144 class S2 {
 145 public:
 146   void advance();
 147
 148   S2 operator++();
 149   S2 operator++(int);
 150   S2 operator--();
 151   S2 operator--(int);
 152   S2 operator=(int);
 153   S2 operator*=(int);
 154   S2 operator/=(int);
 155   S2 operator%=(int);
 156   S2 operator+=(int);
 157   S2 operator-=(int);
 158   S2 operator<<=(int);
 159   S2 operator>>=(int);
 160   S2 operator&=(int);
 161   S2 operator|=(int);
 162   S2 operator^=(int);
 163 };
 164
 165 // Test overloaded operators
 166 void test_overloaded_operator() {
 167   S2 x;
 168   int y;
 169   for (; y < 10; x++, y++) {}
 170   for (; y < 10; ++x, y++) {}
 171   for (; y < 10; x++, ++y) {}
 172   for (; y < 10; ++x, ++y) {}
 173   for (; y < 10; x--, ++y) {}
 174   for (; y < 10; --x, ++y) {}
 175   for (; y < 10; x = 5, ++y) {}
 176   for (; y < 10; x *= 5, ++y) {}
 177   for (; y < 10; x /= 5, ++y) {}
 178   for (; y < 10; x %= 5, ++y) {}
 179   for (; y < 10; x += 5, ++y) {}
 180   for (; y < 10; x -= 5, ++y) {}
 181   for (; y < 10; x <<= 5, ++y) {}
 182   for (; y < 10; x >>= 5, ++y) {}
 183   for (; y < 10; x &= 5, ++y) {}
 184   for (; y < 10; x |= 5, ++y) {}
 185   for (; y < 10; x ^= 5, ++y) {}
 186 }
 187
 188 class Stream {
 189  public:
 190   Stream& operator<<(int);
 191 } cout;
 192
 193 // Confusing "," for "<<"
 194 void test_stream() {
 195   cout << 5 << return_four();
 196   cout << 5, return_four();
 197   // expected-warning@-1{{comma operator}}
 198   // expected-note@-2{{cast expression to void}}
 199   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:3-[[@LINE-3]]:3}:"static_cast<void>("
 200   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:12-[[@LINE-4]]:12}:")"
 201 }
 202
 203 void Concat(int);
 204 void Concat(int, int);
 205
 206 // Testing extra parentheses in function call
 207 void test_overloaded_function() {
 208   Concat((return_four() , 5));
 209   // expected-warning@-1{{comma operator}}
 210   // expected-note@-2{{cast expression to void}}
 211   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:11-[[@LINE-3]]:11}:"static_cast<void>("
 212   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:24-[[@LINE-4]]:24}:")"
 213
 214   Concat(return_four() , 5);
 215 }
 216
 217 bool DoStuff();
 218 class S9 {
 219 public:
 220  bool Advance();
 221  bool More();
 222 };
 223
 224 // Ignore comma operator in for-loop initializations and increments.
 225 void test_for_loop() {
 226   int x, y;
 227   for (x = 0, y = 5; x < y; ++x) {}
 228   for (x = 0; x < 10; DoStuff(), ++x) {}
 229   for (S9 s; s.More(); s.Advance(), ++x) {}
 230 }
 231
 232 // Ignore comma operator in templates.
 233 namespace test_template {
 234 template <bool T>
 235 struct B { static const bool value = T; };
 236
 237 typedef B<true> true_type;
 238 typedef B<false> false_type;
 239
 240 template <bool...>
 241 struct bool_seq;
 242
 243 template <typename... xs>
 244 class Foo {
 245   typedef bool_seq<((void)xs::value, true)...> all_true;
 246   typedef bool_seq<((void)xs::value, false)...> all_false;
 247   typedef bool_seq<xs::value...> seq;
 248 };
 249
 250 const auto X = Foo<true_type>();
 251 }
 252
 253 namespace test_mutex {
 254 class Mutex {
 255  public:
 256   Mutex();
 257   ~Mutex();
 258 };
 259 class MutexLock {
 260 public:
 261   MutexLock(Mutex &);
 262   MutexLock();
 263   ~MutexLock();
 264 };
 265 class BuiltinMutex {
 266   Mutex M;
 267 };
 268 Mutex StatusMutex;
 269 bool Status;
 270
 271 bool get_status() {
 272   return (MutexLock(StatusMutex), Status);
 273   // expected-warning@-1{{comma operator}}
 274   // expected-note@-2{{cast expression to void}}
 275   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:11-[[@LINE-3]]:11}:"static_cast<void>("
 276   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:33-[[@LINE-4]]:33}:")"
 277   return (MutexLock(), Status);
 278   // expected-warning@-1{{comma operator}}
 279   // expected-note@-2{{cast expression to void}}
 280   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:11-[[@LINE-3]]:11}:"static_cast<void>("
 281   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:22-[[@LINE-4]]:22}:")"
 282   return (BuiltinMutex(), Status);
 283   // expected-warning@-1{{comma operator}}
 284   // expected-note@-2{{cast expression to void}}
 285   // CHECK: fix-it:{{.*}}:{[[@LINE-3]]:11-[[@LINE-3]]:11}:"static_cast<void>("
 286   // CHECK: fix-it:{{.*}}:{[[@LINE-4]]:25-[[@LINE-4]]:25}:")"
 287 }
 288 }
 289
 290 // PR39375 - test cast to void to silence warnings
 291 template <typename T>
 292 void test_dependent_cast() {
 293   (void)42, 0;
 294   static_cast<void>(42), 0;
 295
 296   (void)T{}, 0;
 297   static_cast<void>(T{}), 0;
 298 }
 299 #endif  // ifdef __cplusplus